Centrifugal fan or pump.



W. HESSLING. GENTRIFUGAL FAN 0R PUMP.

APPLICATION FILED AUG. 25, 3.911v

Patented May 20, 1913.

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-inssLING or LoNnoN, ENGLAND,` AssIeNon :ro s'rUn'rnvAN'r iiNet- '-NnEnINGooNPANY, LINITED, or L'oNnoN, ENGLAND.-

a citizen of the United `Statesv,',residng at London, En land, have invented certain newA and use ul Improvements in Centrifufffgal Fans or Pumps; and I do hereby declare thefollowing to be a fullz clear, and exact description of theinventlon', suchI as will ena bleothers skilled in the .art to which it` lofppertains make and use the same.

This invention has reference to the class or type of rotary fans and pumps in which the Huid operated on is drawn in centrally and discharged centrifugally and the object of my invention is to obviate certaindef 4f ects inherent in such fans as heretofore made as will be hereinafter made clear..

' 'res 'Such fans or pumps usually consist of a; 'multi-bladed drum rotated by a central shaft. the Vfluid being admitted. at one side ntothe drum iman axial direction and discharged therefrom circumferentially. Such. -f drums are rotated at a fairly and-a matter ofvconsiderableimportance is n that the free and natural movement of the Ailuill from within the drum/to the 4blades highl speed constituting'said drum be Anot interfered with or obstructed as.-otherwise a loss of eiciency foraJ given speed lof rotation as` well as for a'given expenditure of power Another l matter @if considerable importance is.v that the rotating parts shall be constructedl-'and supported so as to be well and properly balanced, as otherwise a limit to the speed of rotation at whlch the parts may I safely be run is soonl reached, th1snecessitating the employment of a larger fanior pump for a given'result than would be nec.I '.40

y'of two Ways, each of which possesses advartages as well as disadvantages compared v essaryif the arts wereproperly balanced.

Heretofore the drums of ssuch fans o r.

pumps have `been usully -supported. in one with the other.

One way is to support the drum by arms or spokes springing from a boss fixed on the driving shaft and connected to the drum lat points inl a' plane located vcentrally-. lengthwise-,of said drum. The other way is to connect thedrum (or the blades constitutingA the drunr) .at one end to-a disk mounted on c e l the rotatmgl'fan or pump. blades during 'cEN'rnxrUoAL FAN on rma?.

Speoicationiof Letters Patent. Appunti@ mea August 25, 1911.

Serial No. 645,970.

v'port the rotating parts aref well. balanced Patented Mayzo, 1913.

. By the former-or V arm method of sup-, v

and may with safetybe run at a yvery high inafter) that the arms as .heretofore made interfereseriously with the free and natural movement of the fluid from within the drum `to the blades. This defect isfavoided' when a drum is carried at one end by a 'disk or equivalent, but by reason of such one-sided vided with a ring or annulus. This tendency to deformation andy consequent vrisk of bursting has been recognized byfan makers, andI to overcome the diiliculty,` the free or open end of the drum has been connected by supporting of the drum theproper balance tie-rods to aboss orl disk on the driving. .l

shaft, but as these -rods ass angularly .across the space wit-hinthe. rum, theirsemplo ment imports the 'defect inherent in t e arm supported drum,- already referred to, in: that said rods seriously interfere with the free and natural passage ofthe duid from within/the drum to the blades.' Furr ther, the drums (whether supported cen trally by arms or on one side by ak disk) have also beenl provided with plates or blades projecting into the-space inclosed by theffan blades, to add stiffness .and rigidity thereto,- but as heretofore made such plates have most seriously interfered with the free and natural movement of the' fluid fromA Within fthe drum to .the yfan blades.

/My i'i'ventionconsists in'y afan or 'pump of the type' referred to xix/@thriving strength'-4 ening plates, or blades ',tktendin'g .into theA space in closed bythe fan'or pump blades in."[ :which the strengthening/or stiieningy platen-WL` are shaped in the direction of rotation to a.

curve which is coincident with the natural path'of movementolfthe Huid relatiyely to movement from the interior to the inner periphery of the drum constituted by the blades. .l

Another feature of my invention consists in supporting the drum by one or more-sets of arms which are made,'or portionsof which are made to a curve'similar to .that referred to with respect to the plates.v

In the accompanying drawings, Figure 1 shows in diagrammatic sectional View, transverse to `the axis, a portion of a drum embodying my invention; Fig. 2 is a longitudinal sectional view of a drum in a casing, the upper portion of the drum being sho-wn as supported by a single set of arms, while the lower portion is shown as supported upon double arms; and Fig. 3 is a transverse sectional view of the drum apart from the casing. r

In the illustrated embodiment ofthe present invention shown in the drawings, the drum-A comprises the rings A1, to which the ends of the blades B are secured. The drum is mounted upon and rotated by the shaft C by means of the supporting arms D, which are arranged in a single plane or in pairs, as shown in Fig. 2. These arms are attached to the strengthening or stifening plates E,which project inwardly beyond the innerperiphery of the blades B. Preferably the drum is mounted in a snail-shaped casing F, as is the general practice with this type of fan. Although this casing is shown with a single intake opening on one side thereof, it is obvious that the drum is 'equally well adapted for use. with a casing having an inlet opening on each side thereof. When the drum is rotated, the Huid will flow radially toward the inner periphery a.

of the drum, as indicated by the broken lines a1, (see Fig. 1); but while the Huid is so moving, the blades B will be constantly moving at right angles thereto and in a circular path, so that relatively tothe moving blades B the fluid is moving in a path which is indicated by broken lines 1 and which is found to be a true logarithmic spiral if the acceleration of speed at which the fluid` It will be seen from `the diagram thatif the support-arms and the inwardly extending plates were made radial, they would constantly cross the natural path (b1) of movement'ofvthe fluid from theiinterior to the inner periphery of the c' `um,.avnd this is `drum is rotated is sufficient to very appreciably reduce the eciency of the fan or pump for a given expenditure of power.

If the arms and plates be made'rcurved, such loss in eiliciency will occur unless the form of curve be that hereinbefore indicated and the nearer to that curvethat thel shape of the armsand plates approaches, theless will be the loss in etliciency.v l

Each of the plates E i'smade to extend to the outer periphery d of thedrum" and the portion situated between-and connected to the rings 'A1 is shaped to act as one of the fan or pump blades. It must-here be observedfthat although the fan pump blades l B areyi'nclosed at their ends by rings A1, thev plates E (except'the parts referred to which serve as fan or pump blades and are located between the rings A1) are not inclosed or provided with anyv shrouding. This is essential, as otherwise the volumetric eiiciency of the fan or pumpis very greatly reduced owing to the obstruction of thefluid in its movement axially into the drum.

Owing to the greatly reduced linear speed of the arms near their axis of rotationas compared with that at or near the periphery of the drum, comparativelyv slight resistance only is set up if the arms near to their ju'nci ture with the boss carrying themicut across.;

the path of movement of the fluid;vv and it may be advantageous for obtaining greaterv strength to make the arms radial nearthe center of the drum about as shown in Fig. My invention is not therefore limited"V to).

arms, the Whole'ofwhich are made curvedv as described. As the plates E are made .ofy

a width corresponding substantially to the length of the drum, these should beinade for their full depth to have the shape described.'

While I have shown in the accompanying drawings, and describedv in the foregoing specification what is now considered a preferred embodiment of my invention and the several features thereof', my invention, except where so specifically defined in the claims is not limited to such illustrated lembodiment, but may beembodied in other 'conf-v structions containing only one or more off said features, and d ilfering in?4 form and arrangement of parts from thatabove shown l and described.

izo

Having thus describedmy invention,l

I claim is :1- Y, Y fr 1. Ina centrifugal 'fan or pump, the com`- bination with. a plurality of blades arranged' in substantially drum Vforinl of a plurality of strengthening plates projecting,inwardly beyond the inner edges ofy the blades. `the' inwardly projecting portion of the plaies be l, ing shaped in the direction of their rot-.uien

"lato, a5

logarithxnic spiral withthe advancing face et,suchuportionconve and meansyfor supporting asdescribedV.

conforming" substantially lgto =a .the blades and' plates, s ubstantial'ly-vv .2. E1n a centrifugal'fan or pumpfthe combinationwitli a plurality of blades arranged `in substantially drum form, ofawplurality inwardly `projecting I.' rof: Strengthening plates projeetjngiinwardly ,beyond` the inner edges of .tli'e l'l'afdes` the portion of the plates Abeing 'shaped inthedlrection qfftheir rota ,ation to a curve conforming substantially.- to .a logarithmic spiral with thevadvancing face l15;',y

of. such portion convex andi.; supporting farms `l attached to and corresponding in- @curvature with. the plates, `smbstantially as vibin'ation with a pluralit described.

3) VIn a centrifugal fan lvor puinp"` `the. comof blades. arranged :J-insubstantially drurn orm, certambf said 4bladesprojecting inwardl Abeyond'theinner yedges 'of theother blades, the 4inwardly projecting portions of saidblades beiiigffshaped in the direction of their rotation` to a curve conforming. substantiallyto a. logarithmic spiral with the advancing faces of such pro` jectionsv convexzmf supporting, arms attached to said inwardly` projecting blades, substantially as described. u

4. In a centrifugal fan or pmp,the comstantially to alogarithmic spiral with the sof supporting arms shaped in the direction l of their rotation to a curve conforming sub-- yadvancing facesy of the arms convex, substantially as described.

5. In a centrifugal fan or pump, the comli- `hination with a plurality of blades arranged in substantially drum form, the advancing faces of the blades being concave, certa-in of bination with a plurality of blades arranged in substantall druni form, the advancing faces ofthe blades being concave, certain of `the blades being formed with portions p rof- ]'ecting inwardly beyond the inner portion of the other blades toform-strengthening plates, the inwardly projecting portions of said blades having their. advancing faces convex, and means for'supporting. the blades 50 and platesg'substantially as described.

` WALDEMAR HEssLING.

bination with a-pluralitv of bld'desarranged itv in substantially drum form, of a plura O. I'. WORTH. 

